1. Field of the Invention
The present invention relates to an antenna device and electronic device. Specifically, the present invention relates to an antenna device that is applied in a portable electronic device with a small-sized housing having a wireless communication function.
2. Description of the Related Art
In recent years, portable electronic devices including various wireless communication functions have been significantly widespread.
Among various electronic devices such as smartphones (high-functionality portable telephones), tablet-type terminals, digital cameras, sports watches (running watches), and GPS devices for mountaineering, those having a function for connecting to a public wireless communication circuit (such as a portable telephone circuit or high-speed data communication circuit), a short-range wireless communication function such as a wireless LAN (Local Area Network) or Bluetooth (registered trademark), or a function for position measurement using electromagnetic waves from a GPS (Global Positioning System) satellite have been known.
In particular, recently, because of rising health consciousness or diversification of interest, more and more people are performing daily exercises, such as walking, running, and cycling, to maintain their wellness or improve their health condition, or are interested in spending time in nature by mountaineering, trekking, etc.
Sports watches, electronic devices for outdoor use, and the like to be used in these scenes are required to have high functionality in addition to light weight and small size, including the short-range wireless communication function such as a wireless LAN (Local Area Network) or Bluetooth (registered trademark), the measurement function by GPS, a time correction function, etc.
Currently, various devices addressing these demands have become commercially available.
One of these electronic devices is, for example, a wristwatch-type terminal described in Japanese Patent Application Laid-Open (Kokai) Publication No 2011-208945 which has a structure where a square-shaped patch antenna for receiving electromagnetic waves from a GPS satellite has been arranged substantially at the center in the housing.
In this type of wristwatch-type terminal, many electronic components are required to be incorporated in a small-sized housing. Therefore, the size of its antenna for GPS and various wireless communications has to be decreased. This decrease in size invites degradation in the performance of the wireless communication, such as degradation in electromagnetic-wave transmission and reception characteristics, and narrowing of the band of the electromagnetic waves.
For example, in a case where a square-shaped patch antenna such as that described in Japanese Patent Application Laid-Open (Kokai) Publication No. 2011-208945 is adopted, it is required to consider the size (area and thickness) of the antenna in order to achieve favorable transmission and reception characteristics.
Here, if the size of the antenna is increased to improve the performance, the layout design of peripheral electronic components and the design of the housing of the wristwatch-type terminal (electronic device) may be affected thereby. Also, the size and structural design of the antenna may be restricted if the size of the housing is decreased and the thickness thereof is made thinner, which decreases the performance of the antenna.